anadian ydrogen ntensity apping xperiment CHIMECHIME CHIMECHIME WiggleZ Dark Ages Stars 13.7Gy CMB Big Bang Reionization 1100 z∞ SDSS 7Gy CHIME 300ky 0 500My Age of Universe Keith Vanderlinde CIfAR C&G 2012 AGM

Outline Cosmo Context HI Mapping of BAO FFT Telescopes CHIME anadian ydrogen ntensity apping xperiment Keith Vanderlinde CIfAR C&G 2012 AGM CHIMECHIME CHIMECHIME

Composition of the Universe Composition Images from NASA / WMAP Science Team w = -1 ± 0.2 Frieman et al Log (a) ? Can study via growth of space. Need standard ruler over wide z range!

The Primordial Plasma Photons Neutrinos Dark Matter Electrons + Baryons Hu & White, Scientific American, 2004

Baryon Acoustic Oscillations random background of primordial fluctuations each fluctuation emits a pressure wave at decoupling, the size of this wave is frozen (Eisenstein) Komatsu et al Cold Stack Hot Stack Measured in the CMB

Post-Decoupling Radial Profile BAO are “frozen in,” ~150 co-moving Mpc. BAO peak Eisenstein

Buetler et al, dFGS BAO Observations Blake et al, 2011 WiggleZ Detected in galaxy correlations! SDSS Eisenstein et al, 2005  m h 2 = 0.12,  m h 2 =  m h 2 = 0.13,  m h 2 =  m h 2 = 0.14,  m h 2 =  m h 2 = 0.105,  m h 2 = 0.0 Sanchez et al, 2012 BOSS-CMASS

BAO as a standard ruler 1100 WMAP... BAO “Size” at z How do we fill this in? Anderson et al. 2012

Optical Maps of Structure Sloan Digital Sky Survey (SDSS) Blanton et al. (2003) Get spectroscopic redshifts on lots of galaxies. Works! But: expensive hard at z>1 BAO Scale BAO Scale

Hydrogen Intensity Mapping For BAO, no need to resolve galaxies individually. Use 21cm HI line. For 15 co-moving Mpc resolution at z~1-2 (~20’), need: Unresolved galaxies, resolved BAO. BAO Scale BAO Scale a)100m telescope + decades of survey b)Interferometer + HUGE correlator c)FFT telescope (See Ue-Li’s talk!)

FFT Telescope Haslam et al Sky Ground E Sampled Ground Measured Sky

Normal Telescope x Use a mirror (or lens) to focus light onto a detector. noise ~ T sky + T amp

x x x x x x x x x Phased Array Interferometer Record signals at the dish, add delay to mimic reflection, sum recorded signals. noise ~ T sky + T amp sqrt(N amp )

Phased Array Interferometer x x x x x x x x x Throw away the dish. Save a big pile of money. noise ~ T sky + T amp sqrt(N amp )

“Pointing” a Phased Array x x x x x x x x x Add delays with cabling to mimic pointing. Spend your pile of money on a computer, do this digitally. noise ~ T sky + T amp sqrt(N amp )

Beam-forming Telescopes x x x x x x x x x Record signals on the ground, digitally delay and add. N beams, without aliasing, for spacing < /2. Mapping speed ~ N ant x single-dish. (N 2 for T sky >> T amp ) noise ~ T sky + T amp sqrt(N ant ) -- per beam! --

Cylinder Telescopes Hybrid: 1D Dish + 1D FFT Single Antenna Long Narrow Beam

Cylinder Telescopes Hybrid: 1D Dish + 1D FFT N antennas N “Formed Beams” FFT

100m MHz band 21cm from z ~ Resolution: 1MHz, 13-26’ <10% BAO scale Drift scan, no moving parts 20,000 deg 2 coverage C anadian H ydrogen I ntensity M apping E xperiment

1 2 Record Data Readout & Correlator 1) Sample & channelize 1 ADC per antenna 800MSPS 2) Correlate 1 node per freq band N 2 is tricky: Pflops of processing, Exabytes of storage (!!) Do FFT beamforming, plus partial N 2 to calibrate

CHIME Sensitivity to BAO spectrum w/ BAO spectrum w/o BAO

CHIME Cosmology Forecast (1+z) 3 ^ (Preliminary!)

Pulsars & Radio Transients Every day, CHIME observes: every point in the northern celestial hemisphere across an octave in frequency ( MHz) for between 5 minutes and hours (depending on Decl.) with  s timing resolution & accuracy Can’t actually process every point at that rate. Tee data off to monitor known locations, systematically search for new sources.

Mapping the Observable Universe Dark Ages WiggleZ Stars 13.7Gy CMB Big Bang Reionization SDSS 1100 z∞ Gy CHIME (400 co-moving Gpc 3 ) 300ky 0 500My Age of Universe CHIME will: survey BAO measure the growth of space from 0.8<z<2.5 over a volume of ~400 co-moving Gpc 3

CHIME Survey Volume For cosmic variance limited survey, sensitivity ~ volume. CHIME’s sensitivity to D.E. within ~2x of c.v. limited.

The End